1. Field of the Invention
This invention relates in general to the field of microelectronics, and more particularly to apparatus and methods for providing compressed configuration data in a fuse array associated with a multi-core device.
2. Description of the Related Art
Integrated device technologies have exponentially advanced over the past 40 years. More specifically directed to the microprocessor fields, starting with 4-bit, single instruction, 10-micrometer devices, the advances in semiconductor fabrication technologies have enabled designers to provide increasingly more complex devices in terms of architecture and density. In the 80's and 90's so-called pipeline microprocessors and superscalar microprocessors were developed comprising millions of transistors on a single die. And now 20 years later, 64-bit, 32-nanometer devices are being produced that have billions of transistors on a single die and which comprise multiple microprocessor cores for the processing of data.
One requirement that has persisted since these early devices were produced is the need to initialize these devices with configuration data when they are turned on or when they are reset. For example, many architectures enable devices to be configured to execute at one of many selectable frequencies and/or voltages. Other architectures require that each device have a serial number and other information that can be read via execution of an instruction. Yet other devices require initialization data for internal registers and control circuits. Still other devices utilize configuration data to implement redundant circuits when primary circuits are fabricated in error or outside of marginal constraints.
As one skilled in the art will appreciate, designers have traditionally employed semiconductor fuse arrays on-die to store and provide initial configuration data. These fuse arrays are generally programmed by blowing selected fuses therein after a part has been fabricated and the arrays contain thousands of bits of information which is read by its corresponding device upon power-up/reset to initialize and configure the device for operation.
As device complexity has increase over the past years, the amount of configuration data that is required for a typical device has proportionately increased. Yet, as one skilled in the art will appreciate, though transistor size shrinks in proportion to the semiconductor fabrication process employed, semiconductor fuse size increases to the unique requirements for programming fuses on die. This phenomenon, in and of itself, is a problem for designers, who are prevalently constrained by real estate and power considerations. That is, there is just not enough real estate on a given die to fabricate a huge fuse array.
In addition, the ability to fabricate multiple device cores on a single die has geometrically exacerbated the problem, because configuration requirements for each of the cores results in requirement for a number of fuses on die, in a single array or distinct arrays, that are equal to the number of cores disposed thereon.
Therefore, what is needed is apparatus and methods that enable configuration data to be stored and provided to a multi-core device that require significantly less real estate and power on a single die than that which has heretofore been provided.
In addition, what is needed is a fuse array mechanism that can store and provide significantly more configuration data than current techniques while requiring the same or less real estate on a multi-core die.